The Guardian said it decided to bring in a US partner in order to continue reporting on the GCHQ files. Photograph: Andrew Cowie/AFP/Getty Images

The Guardian has struck a partnership with the New York Times which will give the US paper access to some of the sensitive cache of documents leaked by the National Security Agency whistleblower Edward Snowden.

The arrangement was made when the Guardian was faced with demands from the UK government to hand over the GCHQ files it had in its possession.

"In a climate of intense pressure from the UK government, the Guardian decided to bring in a US partner to work on the GCHQ documents provided by Edward Snowden. We are working in partnership with the NYT and others to continue reporting these stories," the Guardian said in a statement.

Journalists in America are protected by the first amendment which guarantees free speech and in practice prevents the state seeking pre-publication injunctions or "prior restraint".

It is intended that the collaboration with the New York Times will allow the Guardian to continue exposing mass surveillance by putting the Snowden documents on GCHQ beyond government reach. Snowden is aware of the arrangement.

The collaboration echoes that of the partnership forged in 2010 between the Guardian, the New York Times and Der Spiegel in relation to WikiLeaks's release of US military and diplomatic documents.

The US surveillance scandal broke in early June when the Guardian revealed the US was collecting telephone records of millions of American citizens.

Since then the Guardian has exposed mass surveillance of Facebook, Google, Microsoft, eavesdropping by Britain's GCHQ on foreign politicians at G20 summits in London and the secret operation codenamed Tempora, involving mass interception of cable traffic, designed, in the words of GCHQ to "Master the Internet".